Battle of Aichach

The Battle of Aichach (late January 1806) was the first major battle of the War of the Fourth Coalition. The Prussian army, led by Prince Louis Ferdinand of Prussia, attempted to capture Munich but halted to the north of the city to encamp and replenish their strength. The Confederation of the Rhine (effectively a part of the French Republic) sent Pierre-Francois Rapp and 10,300 French troops north from Munich to attack the 11,900 Prussian troops in the snow, but their attacks were repulsed and Munich fell in February.

Background
In 1805 the Austrian Empire, Russian Empire, Great Britain, Sweden, Naples & Sicily, and the nations of Baden and Wurttemberg declared war on the newly-formed French Empire, forming the third coalition against France within ten years. France's Emperor Napoleon I proclaimed that all of the territories along the Rhine allied with France were now under French "protection", forming the Confederation of the Rhine. The confederation members were effectively French possessions, as they were ruled directly from Paris. Mustering up large forces under his Grande Armee, Napoleon invaded his rivals' territories. The Allies were decisively defeated at the Battle of Austerlitz in the present-day Czech Republic in December 1805 and by January 1806, France was pushing into Russian territories.

Prussia had stood idle in the Napoleonic Wars, but formed a defensive alliance with Russia in January 1805, angering Napoleon. Prussia waited it out, watching to see if they should ally with France or Austria, observing where their benefits lay. Eventually, Prussia found that France was an expanding menace and - after annexing all of the small German states to "protect them from France" - Prussia mobilized on the border. Napoleon declared war on Prussia in late 1805 but made peace after Prussia conquered Hannover. However, in early 1806 Napoleon was ready to try again and declared war once more. Prussia allied itself with the other coalition members, forming the Fourth Coalition.

As of early 1806, Prussia had control of much of present-day Germany as well as Poland and the Netherlands. They annexed Baden-Wurttemberg at the end of 1805, prying all of the Confederation of the Rhine's member states, bar Bavaria, out of Napoleon's pockets. King Friedrich Wilhelm III of Prussia, who had occupied Stuttgart in Baden-Wurttemberg, ordered his uncle Prince Louis Ferdinand of Prussia to lead an army from Hesse-Kassel south into Bavaria, the last Confederation of the Rhine state.

Louis Ferdinand, Prinz von Preussen, was in control of 11,900 Prussian troops, and moved out to capture Munich. However, he had to set up camp north of the city, as his men were fatigued from the long southwards march. The garrison of Munich, some 10,300 troops under Pierre-Francois Rapp, moved north to attack the Prussians. Although the Prussians had more troops, they were made up of Landwehr militia troops, while the French had Fusiliers of Line.

Initially, the Prussians decided to withdraw over the High Rhine River and reach the other side, where they could march back to Hesse-Kassel in a week. However, the French/Confederation of the Rhine troops pursued them and the Prussians were forced to give battle at Aichach.

Battle
The Prussian army lined up in a long line, with most of their artillery positioned in the center but one unit on the right flank. France's army lined up in a shorter line, because they had less troops. Louis Ferdinand deployed extra militia from the right flank behind the weak skirmishers and anarchy on his left flank, reinforcing them in the case of a French cavalry charge. He moved his gunnery regiment from the right to the left in a more open area, and also in the line of sight of French troops, as the original position put them far away from the French army. The Prussians banded up rather than spread themselves too thin.

The French launched a cavalry charge of Chasseurs a Cheval on the Prussian right flank, but they were repelled by Prussian landwehr, and colonel Florentin Wernz was killed. The French attempt to charge in the Prussian center also failed, while some Prussian hussars snuck around the French army and took out their cannon behind their main army. Without artillery, the French were forced to launch a full-scale attack on the Prussians if they wanted to drive the Prussians from the field.

Rapp personally led a charge of Chasseurs a Cheval, hoping to spur on the advance of his men. Prussian gunfire routed the French Fusiliers of Line, who faced a much larger army. Rapp was killed by grapeshot from Prussian cannon and his army was routed with heavy losses. 9,690 French and 3,290 Prussian troops were lost, enabling Prussia to go on and take Munich.

Aftermath
The Prussian army of Prince Louis Ferdinand went on to accept the surrender of the French garrison of the city of Munich, and Bavaria fell to Prussia. France was not nearly defeated, however; their armies occupied the Prussian provinces of West Prussia and East Prussia, while they made advances in Italy by capturing Innsbruck and Milan from the Austrian Empire. The victory was still a morale boost for the people of Prussia, who had been angry at the bankruptcy of their country.